# CVE-2026-93640: Zimbra Collaboration Suite Local Privilege Escalation via Unrestricted zmunbound Sudo Configuration


- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 23 Oct 2026
- **Updated:** 24 Oct 2026
- **Also known as:** GHSA-m5xr-vr49-p6gj

## What is CVE-2026-93640?

CVE-2026-93640 is a high-severity vulnerability in Zimbra Collaboration Suite, published on 23 Oct 2026. 

### Official description

A local privilege escalation vulnerability in the optional dnscache package of Zimbra Collaboration Suite (ZCS) allows the Unix zimbra account to access files with root privileges. The passwordless sudo policy permits arbitrary arguments to zmunbound, whose wrapper forwards them to Unbound without restricting the configuration path. An attacker can supply a configuration that retains root privileges and disables the chroot. Include directives expose root-readable file contents through parser errors, while an attacker-selected logfile path creates a root-owned file or appends Unbound log records to an existing file. This can disclose password hashes and private keys and corrupt privileged configuration files, preventing affected services from starting with the modified configuration. The affected configuration is present in ZCS 10.1.16 and 10.1.21 dnscache packages.

Weakness: CWE-732 (Incorrect Permission Assignment for Critical Resource)

## Which versions are affected by CVE-2026-93640?


## How do I fix CVE-2026-93640?

No fix has been published for CVE-2026-93640 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-93640 being exploited?

There is no known exploitation of CVE-2026-93640 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93640 and fix it if it is affected.

What it is: CVE-2026-93640 is a high-severity vulnerability in Zimbra Collaboration Suite, published on 23 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-93640 in the wild and no public exploit code.

Affected product: Zimbra Collaboration Suite. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-93640/ (Markdown: https://insights.sbomify.com/CVE-2026-93640/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93640
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93640
- OSV: https://osv.dev/vulnerability/CVE-2026-93640

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93640/
Summaries are generated and may contain mistakes; the official description above is the record.